Arm

Question 1

Coracobrachialis IO Action Innervation

Answer 1

Origin:
* Coracoid process of scapula

Insertion:
* Middle 3rd of medial aspect of humerus

Action:
* Adduction of humerus
* Flexion of humerus

Innervation:
* Musculocutaneous nerve

Question 2

Biceps brachii IO Action Innervation

Answer 2

Origin:
* Short head: Apex of coracoid process of scapula
* Long head: Supraglenoid tubercle of scapula; Glenoid labrum

Insertion:
* Radial tuberosity
* Antebrachial fascia

Action:
* Flexion of humerus
* Flexion of forearm at elbow when supinated
* Supination of forearm

Innervation:
* Musculocutaneous nerve

Question 3

Brachialis IO Action Innervation

Answer 3

Origin:
* Anterior aspect of distal ½ of humerus

Insertion:
* Coronoid process and tuberosity of ulna

Action:
* Flexion of forearm at elbow in all positions

Innervation:
* Musculocutaneous nerve
* Radial nerve (small contribution to lateral part of muscle)

Question 4

Triceps brachii IO Innervation

Answer 4

Origin:
* Lateral head: Posterior surface of humerus, superior to radial grove
* Long head: Infraglenoid tubercle of scapula
* Medial head: Posterior surface of humerus, inferior to radial grove

Insertion:
* Olecranon of ulna
* Adjacent antebrachial fascia

Innervation:
* Radial nerve

Question 5

Triceps brachii Action

Answer 5

• Extension of forearm at elbow

Long head:
* Extension of humerus
* Adduction of humerus